Filter element and mounting method

ABSTRACT

The present invention relates to an apparatus for filtering a gas or liquid stream such as a natural gas stream. The apparatus includes a closed vessel having a longitudinally extending length, an initially open interior, an input port at one extent and an output port at an opposite extent thereof. A partition located within the vessel interior divides the vessel interior into a first stage and a second stage. At least one opening is provided in the partition. A filter element is disposed within the vessel to extend from within the first stage. The filter element is easily mounted or removed from the vessel by rotating a J-slot engagement surface on the element which mates with a post provided on a mounting structure provided on the vessel partition.

BACKGROUND ART

1. Field of the Invention

The invention relates to filter vessels used to filter gas and liquidstreams such as natural gas and natural gas processing liquid streamsand to filter elements for such vessels, and, more specifically, to animproved structure and method for mounting the filter elements withinthe interior of the associated filter vessel.

2. Description of Related Art

Gas filter elements for filtering dry gas streams as well as forseparating solids and liquids from contaminated gas streams are wellknown, as are gas filter elements for coalescing entrained liquids froma gas stream. Often these types of gas filter elements are installed inmulti-stage vessels, which are in turn installed in a gas pipeline, toperform these filtering functions. U.S. Pat. No.'s 5,919,284, issuedJul. 6, 1999, and U.S. Pat. No. 6,168,647, issued Jan. 2, 2001, both toPerry, Jr., and assigned to the assignee of the present invention,disclose multi-stage vessels using individual separator/coalescer filterelements to separate solids, filter liquids, and coalesce liquids. Theforegoing multi-stage vessels, as well as a multitude of other similarfiltration vessels used in industry utilize solid or hollow core tubularelements, typically formed at least party of a porous filtration media.For example, porous filtration elements useful in the above type offiltration vessels are of the same general type as those that aredescribed in U.S. Pat. No. 5,827,430, issued Oct. 27, 1998 to Perry,Jr., et al., and assigned to the assignee of the present invention.

It is periodically necessary to perform maintenance on the filtrationvessels, including replacement of the porous filter elements. This taskhas been labor intensive and time consuming in the past because of themounting structure used to mount the filter elements within thefiltration vessel interior. Often, it was necessary to unscrew and endcap or nut to free the filter element from its associated structuralmounting within the vessel interior. Not only was this time consuming,but the location of the mounting structure was sometimes inconvenient toaccess, making filter replacement a difficult or inconvenient chore. Thesame type of inconveniences were present in the initial filterinstallation process for new filtration vessels.

Thus, despite various advances which have been made in overallfiltration vessel design, there continues to be a need for improvementswhich simplify the process of mounting and replacing filter elementswithin the filtration vessel, thereby decreasing the cost of vesselinstallation and maintenance.

BRIEF SUMMARY OF THE INVENTION

An apparatus is shown for filtering a gas or liquid stream such as anatural gas stream or a natural gas processing liquid stream. Theapparatus includes a closed vessel having a length and an initially openinterior. A partition is disposed within the vessel interior. Thepartition has a planar inner and planar outer side, respectively,dividing the vessel interior into a first stage and a second stage. Atleast one opening is provided in the partition. An inlet port isprovided in fluid communication with the first stage. An outlet portalso provides fluid communication from the second stage. At least onetubular filter element is disposed within the vessel to sealingly extendwithin the first stage. Each filter element has a locking end, a tubularlength and a handle end. A mounting structure is located on a selectedplanar side of the partition. Rotational mounting means are provided onthe locking end of at least selected filter elements which meanscooperate with the mounting structure of the vessel for rotationallylocking the filter element with respect to the partition upon rotationalmovement of the filter element from the handle end.

Preferably, the locking end of the filter elements is a generallycylindrical surface which forms an end opening and the mounting meansprovided on the locking end of the filter elements is a slot provided inthe cylindrical surface. The most preferred mounting means provided onthe locking end of the filter element is a J-slot. The generallycylindrical locking end of the filter elements joins the tubular lengthof the filter elements at a neck region of each filter element. The neckregion forms a region of increased external diameter along the tubularlength of the filter element. A seal means is located at the neck regionfor sealing against the partition when the filter element is locked in afully engaged position. The preferred seal means can comprise achevron-shaped seal or an O-ring seal. The preferred mounting structurelocated on a selected side of the partition is a continuous post, or apair of spaced post elements, aligned with respect to the partitionopening, wherein the J-slot receives and engages the post or pair ofpost elements as the filter element is rotated from the handle end.

The filter elements each have a filter wall and can have hollow cores.The input port, vessel interior, tubular filter elements and output porttogether define a flow passage within the apparatus. The gas streamflows into the first stage through the input port and through the outerfilter wall of the filter element and through the hollow filter core,thereby separating impurities out of the gas stream. The gas stream thenflows out of the second stage through the outlet port. The preferredtubular filter elements consist of multi-overlapped layers of non-wovenfabric strips.

A method is also shown for installing a filter element within afiltration vessel used to filter gas, liquid and gas/liquid streams. Afilter vessel is provided as previously described having a first andsecond stage divided by a partition. At least one replaceable filterelement is installed within the filter vessel. The filter element isprovided with the previously described locking end, tubular length, andhandle end. The filter element is installed within the vessel byrotationally locking the filter element with respect to the partitionupon rotational movement of the filter element from the handle end.

The above as well as additional objects, features, and advantages of theinvention will become apparent in the following detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side elevational view in partial section of a filter vesselhaving a filter element of the invention installed therein.

FIG. 2A is partial, end view of a filter element of the inventionshowing the element engaged within the vessel mounting structure.

FIG. 2B is an isolated view of the handle end of the filter element ofthe invention.

FIG. 3A is a side, sectional view of a filter element of the inventionshown disengaged from the associated vessel mounting structure, thefilter element having a chevron-shaped seal.

FIG. 3B is a view similar to FIG. 3A but with the filter element shownin the engaged position with respect to the vessel mounting structure.

FIG. 4A is a view of an alternative filter element design showing anO-ring type seal for engaging the associated vessel mounting structure.

FIG. 4B is a view of the filter element of FIG. 4A engaged with thevessel mounting structure.

FIG. 5 is a view of a prior art filtration vessel showing the method ofmounting the filter elements therein.

FIG. 6 is a simplified, side view of a conventional filter element whichis used in retrofit fashion within the filter vessel of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Turning to FIG. 1 there as shown a filter vessel of the inventiondesignated generally as 13. The apparatus 13 is shown in its simplestform as a dry-gas filter. The internals or filter element shown in unit13, illustrated in FIG. 1, would typically be followed by a second stagemist extractor of the type commercially available in the industry. WhileFIG. 1 illustrates one embodiment of a natural gas filtration vessel, itwill be understood by those skilled in the art that the filter elementsand method of mounting covered by the present invention can be appliedto a variety of such vessels used in the industry. For example, thefilter elements of the invention might be employed in vessels which areused for simultaneously filtering solids, separating liquids,pre-coalescing liquids, and coalescing liquids out of a gas stream. Thefilter elements might also be utilized in vessels used for coalescingand separating two liquids and for filtering solids out of liquids.Also, while the vessel shown in FIG. 1 illustrates one filter elementmounted within the vessel for simplicity of illustration, it will beunderstood that some vessel designs will employ multiple elementsutilizing the attachment means of the invention in a single vessel.

Referring again to FIG. 1, it should be understood that although thevessel 13 is shown in a generally horizontal configuration, it may alsobe configured in a generally vertical embodiment. The vessel 13 has agenerally tubular shell 15 having an initially open interior 17. Theshell 15 is enclosed at an inlet end 19 by means of a closure member 21which, in this case, is a bolted flange. The shell 15 is permanentlyenclosed at an outlet end 23 by a cap 25, preferably elliptical. Theflanged closure 21 provides a fluid tight seal with respect to the inletend 19. In the embodiment of FIG. 1, a single filter element 27 issupported within the vessel open interior 17 by means of a vesselpartition 29 and support element 31. The support element 31 can comprisea flat bar or expanded metal.

The partition 29 divides the hull interior into a first stage 35 and asecond stage 33. The vessel 13 is preferably manufactured of steelmaterials which conform to published pressure-vessel standards, such asASME Boiler and Pressure Vessel Code, Section VIII, Division 1.

The partition 29 which divides the vessel interior into the first andsecond filtration stages has a planar inner and planar outer opposingsides 37, 39, respectfully. At least one opening 41 is provided in thepartition for receiving an end of the filter element. An inlet port 45is in fluid communication with the first stage and an outlet port 43 isin communication with the second stage. The tubular filter element 27 isdisposed within the vessel to sealingly extend within the first stage 35through one of the openings 41 in the partition 29 into the second stage33. Gas flow is through the inlet port 45, through the filter wall, ofthe filter element, through the hollow core 47 of the filter element,and through the second stage to the outlet 43. The direction of the gasflow is indicated by the arrows in FIG. 1.

As best seen in FIGS. 3A and 3B, each tubular filter element 27 has alocking end 49, a tubular length and a handle end 51. As shown in FIG.3A, a mounting structure is located on a selected planar side of thepartition 29. A rotational mounting means is provided on the locking end49 of the filter element 27 which cooperates with the mounting structureof the vessel for rotationally locking the filter element with respectto the partition 29 upon rotational movement of the filter element 27from the handle end 51.

Preferably, the filter element is provided with a generally cylindricallocking end 53 and the rotational mounting means on the locking end ofthe filter element is a slot 55 provided in the cylindrical surface ofthe locking end 53. The preferred mounting means on the locking end ofthe filter element is a J-slot, as illustrated in the drawings. Thegenerally cylindrical locking end 53 of the filter element joins thetubular length of the filter element at a neck region 57. The neckregion 57 forms a region of increased external diameter along thetubular length of the filter element. A seal means is located at theneck region for sealing against the partition 29 when the filter element27 is locked in position. In the embodiment of the invention illustratedin FIGS. 3A and 3B, the seal means is an elastomeric chevron-shapedmember 59. The chevron-shaped seal 59 is shown engaged against thepartition planar inner side 37 in FIG. 3B. The exposed lip 60 of theseal member 59 acts as a resilient spring in holding the overall filterelement in a “locked” or “seal engaged” position (illustrated in FIG.3B).

FIGS. 4A and 4B illustrate another embodiment of the filter element ofthe invention in which the neck region 57 carries an O-ring seal 61, theO-ring seal being received within a mating groove provided on the planarsurface of the neck region. FIG. 4B shows the O-ring seal in engagementwith the planar inner side 37 of the partition 29 when the element is inthe locked in position.

As shown in FIG. 3A, the mounting means which is provided on thepartition 29 can comprise a continuous post 63 which is aligned withrespect to a partition opening 41. As shown in FIG. 3B, the J-slot 55provided in the cylindrical end 53 of the filter element receives andengages the post 63 as the filter element is rotated from the handle end51. The post 63 is, in this case, supported between opposing sideflanges 65, 67 which are arranged to generally perpendicular to theplanar face 39 of the partition 29. In this way, the post 63 extends ina plane generally parallel to the plane of the selected planar face ofthe partition.

As illustrated in FIGS. 4A and 4B, the mounting means which is providedon the partition 29 can also comprise two spaced-apart post elements 62,64, with one post element being attached to each opposing side flange65, 67. The discontinuity in the post 63 (shown in FIG. 3A) helps toreduce the flow restriction in the filter element outlet end caused bythe presence of the mounting structure.

FIGS. 2A and 2B illustrate the respective locking and handle ends of thefilter element 27. FIG. 2A illustrates the rotational mounting means(J-slot 55) fully engaged with the mounting post 63. In this case, thepost 63 is a continuous post which is supported between the opposingside flanges 65, 67, as described with respect to FIGS. 3A and 3B.

The filter elements of the invention can be easily installed or removedfrom within the filter vessel 13. As shown in FIG. 1, the initially openinterior 17 can be accessed by means of the closure 21. The filterelement 27 can removed by simply turning the handle end 51. Rotationalmovement of the handle 51 causes the locking end 49 to rotate, wherebythe J-slot rides about the post 63 (FIG. 2A), thereby releasing theelement. The element can then be withdrawn from the vessel interior 17by sliding the element longitudinally along the horizontal axis of thevessel and out the closure opening. A replacement filter element canthen be easily installed by repeating the above steps in the reverseorder.

The filter vessel 13 can also be retrofitted with an existing,conventional filter element, such as the element 201 shown in FIG. 6. Inthe example illustrated, a single or double open end filter element 201is provided with a sealing plate 203 at one extent. An elementattachment rod 205 is secured to the sealing plate 203 by means ofexternal nut 207 on one end and is supported within an opening 209 inthe partition or tubesheet (29 in FIG. 1) by means of a flat bar 211which fits across the tubesheet opening.

It will be understood by one skilled in the art that other mountingmeans could also be utilized to mount a conventional filter elementwithin the vessel of the invention. For example, the element attachmentrod (205 in FIG. 6) could carry a transverse pipe in place of the flatbar 211 which pipe would have end openings which could be received overthe spaced-apart posts (62 and 64 in FIG. 4A). Other types of engagementmeans could also be carried on the element attachment rod 205.

The bodies, or tubular filter walls of the filter elements of theinvention are preferably constructed in the manner and of the materialsdisclosed in U.S. Pat. No. 5,827,430, issued Oct. 27, 1998 to Perry,Jr., et al. A suitable filter element for use in the present inventionis the PEACH™ filter commercially available from Perry EquipmentCorporation of Mineral Wells, Texas. For example, in a typicalapplication, the filter elements consist of four multi-overlapped layersof non-woven fabric strips of varying composition. The first layer iscomposed of equal amounts by volume of fibers purchased from HoechstCelanese of Charlotte, N.C., United States, sold under the fiberdesignation “252,” “271,” and “224,” has a basis weight of 0.576 ouncesper square foot, is ten inches wide, and is overlapped upon itself fivetimes. The denier of fiber “252” is 3 and its length is 1.500 inches.The denier of fiber “271” is 15 and its length is 3.000 inches. Thedenier of fiber “224” is 6 and its length is 2.000 inches.

The second layer is composed of equal amounts by volume of “252,” “271,”and “224,” has a basis weight of 0.576 ounces per square foot, is eightinches wide, and is overlapped upon itself four times. The third layeris composed of equal amounts by volume of “252,” “271,” and “224,” has abasis weight of 0.576 ounces per square foot, is eight inches wide, andis overlapped upon itself four times. The fourth layer is composed ofequal amounts by volume of “252” and a fiber sold under the name“Tairilin,” has a basis weight of 0.576 ounces per square foot, is sixinches wide, and is overlapped upon itself three times. Fiber “252”being of the core and shell type serves as the binder fiber in each ofthe aforementioned blends.

The above example of particular types of material, fabric denier, numberof wrapping layers, etc., is intended to be illustrative only of thetype of preferred filter materials useful in the practice of the presentinvention. The rotational lock and release feature of the elements ofthe invention could be used with conventional filter materials, as well.

The advantages of the improved filter elements and method of mountingthereof can perhaps best be understood with reference to the prior artfiltration unit shown in FIG. 5 of the drawings. This vessel isdescribed in issued U.S. Pat. No. 6,168,647, issued Jan. 2, 2001, andassigned to the assignee of the present invention. The discussion whichfollows also describes the filtration process in greater detail. Thevessel 111, shown in FIG. 5, is best suited for mist collection. Inaddition, multi-stage vessel 111 is well suited for applicationsinvolving immiscible fluids, and as such, can be used in applicationsrequiring the separation and filtration of two immiscible liquids orimmiscible liquids and gases. The flow of the gas stream is indicatedbelow as arrow G. Multi-stage vessel 111 has a generally tubular hull112 having an initially open interior. Hull 112 is releasably enclosedon an upper inlet end 112 a by a conventional closure member 115,preferably a quick-opening closure. Hull 112 is permanently enclosed ona lower outlet end 112 b by a cap 113, preferably elliptical. Closuremember 115 consists of a conventional head member 116 and a conventionalclamping member 117. Head member 116 is releasably sealed to multi-stagevessel 111 by clamping member 117. Clamping member 117 may be released,and head member 116 may be opened to allow access to the interior ofhull 112. Clamping member 117 provides a fluid-tight seal between hull112 and head member 116, preferably with a conventional O-ring (notshown). A plurality of separator/coalescer filter elements 118 aredisposed within hull 112. Separator/coalescer filter elements 118 areconstructed as described above with respect to the vessel of theinvention. Hull 112 is supported by support members 119. A conventionaldavit assembly supports head 116 when head 116 so that head 116 may beswung open to allow access to multi-stage vessel 111.

The interior of hull 112 is divided into a first stage 121 a and asecond stage 121 b by a generally transverse partition 123. Partition123 includes a plurality of openings 125. A tubular filter guide 127 isaligned with each opening 125. Each filter guide 127 extendslongitudinally a selected distance from partition 123 into first stage121 a. An inlet port 129 is disposed on hull 112 and opens into firststage 121 a. Inlet port 129 terminates with an inlet flange 131. Inletport 129 is located near partition 123 so that as a gas stream flowsthrough the inlet port 129 into first stage 121 a, the gas streamimpinges upon filter guides 127. An outlet port 133 is disposed on hull112 and opens into second stage 121 b. Outlet port 133 terminates withan outlet flange 135. Outlet flange 135 is adapted to allow multi-stagevessel 111 to be connected to a conventional gas pipeline. An annularcollar 136 is aligned with outlet port 133 and extends into second stage121 b.

Disposed underneath portion 112 c of hull 112 is a sump 139 forcollecting the filtered solids, the separated liquids, the pre-coalescedliquids, and the coalesced liquids, that are removed from the gasstream. Sump 139 is divided into a first stage sump 139 a and a secondstage sump 139 b by an impermeable sump partition 141. A first stagedowncomer 143 a provides fluid communication between first stage 121 aand first stage sump 139 a. The second stage downcomer 143 b similarlyprovides fluid communication between second stage 121 b and second stagesump 139 b. A screen member 161 in the lower portion of the second stage121 b acts as a barrier to prevent coalesced liquids that have collectedin the lower portion of the second stage from being re-entrained in thegas stream.

A plurality of first stage support straps 165 are disposed in firststage 121 a to support separator/coalescer filter elements 118. Firststage support straps 165 generally extend transversely across firststage 121 a and are connected to the interior of hull 112 by a snap fitor any suitable holding clip member. First stage support straps 165include a plurality of apertures 166 to receive separator/coalescerfilter elements 118 firmly in place without longitudinal compression.Likewise, a plurality of second stage support straps 167 are disposed insecond stage 121 b to support separator/coalescer filter elements 118.Second stage support straps 167 generally extend transversely acrosssecond stage 121 b and are connected to the interior of hull 112. Secondstage support straps 167 include a plurality of apertures 168 to receiveseparator/coalescer filter elements 118. The filter elements includefilter cap posts 193 a and 193 b.

A plurality of louvered impingement baffles 171 are disposed in secondstage 121 b to prevent coalesced liquids and fine liquids from becomingre-entrained in the gas stream as the gas stream flows through secondstage 121 b toward outlet port 133. A separate louvered impingementbaffle 171 is associated with each separator/coalescer filter element118 and each corresponding opening 125 in partition 123. Each louveredimpingement baffle 171 includes a basket body portion 173 coupled to abasket cap portion 175. Each louvered impingement baffle 171 includes aplurality of annular louvers 177 disposed along the extent of basketbody portion 173.

It will be appreciated from the foregoing discussion that a morecomplicated mounting and support structure are required in the prior artdevice. The improved filter element and mounting method of the inventionprovides several advantages over such a structure. The improved filterelements of the invention utilize a rotational locking feature whichallows the filter element to be easily installed or removed from thefilter vessel interior. The simplicity of the J-slot locking mechanismsimplifies the design of the element and associated mounting structureand provides improved efficiency during installation and maintenanceoperations. The filter locking design is simple in design and economicalto manufacture. The locking mechanism is extremely reliable inoperation.

While the invention is shown in only one of its forms, it is not justlimited but is susceptible to various changes and modifications withoutdeparting from the spirit thereof.

1. An apparatus for filtering a natural gas stream, the apparatuscomprising: a closed vessel having a length and an initially openinterior; a partition disposed within the vessel interior, the partitionhaving a planar inner and planar outer side, respectively, dividing thevessel interior into a first stage and a second stage; at least oneopening in the partition; an inlet port in fluid communication with thefirst stage; an outlet port in fluid communication with the secondstage; at least one tubular filter element, the tubular filter elementbeing disposed within the vessel to sealingly extend from within thefirst stage, the filter element having a locking end, a tubular length,and a handle end; a mounting structure located on a selected planar sideof the partition; a rotational mounting means on the locking end of theat least one filter element which cooperates with the mounting structureof the vessel for rotationally locking the filter element with respectto the partition upon rotational movement of the filter element from thehandle end; and wherein the generally cylindrical locking end of thefilter elements joins the tubular length of the filter elements at aneck region of each filter element, the neck region forming a region ofincreased external diameter along the tubular length of the filterelement, and wherein a seal means is located at the neck region forsealing against the partition when the filter element is locked inposition.
 2. The apparatus of claim 1, wherein the seal means is achevron-shaped seal.
 3. The apparatus of claim 1, wherein the seal meansis an O-ring seal.
 4. An apparatus for filtering a natural gas stream,the apparatus comprising: a closed vessel having a length and aninitially open interior; a partition disposed within the vesselinterior, the partition having a planar inner and planar outer side,respectively, dividing the vessel interior into a first stage and asecond stage; at least one opening in the partition; an inlet port influid communication with the first stage; an outlet port in fluidcommunication with the second stage; at least one tubular filterelement, the tubular filter element being disposed within the vessel tosealingly extend from within the first stage, the filter element havinga locking end, a tubular length, and a handle end; a mounting structurelocated on a selected planar side of the partition; a rotationalmounting means on the locking end of the at least one filter elementwhich cooperates with the mounting structure of the vessel forrotationally locking the filter element with respect to the partitionupon rotational movement of the filter element from the handle end;wherein each of the filter elements has a generally cylindrical lockingend and wherein the mounting means on the locking end of the filterelements is a slot provided in the cylindrical locking end; wherein themounting means on the locking end of the filter elements is a J-slot;wherein the mounting structure located on a selected side of thepartition is a post which is aligned with respect to a partition openingand wherein the J-slot receives and engages the post as the filterelement is rotated from the handle end; and wherein the post issupported between opposing side flanges, the side flanges being arrangedgenerally perpendicular to the selected planar face of the partition,whereby the post extends in a plane generally parallel to the plane ofthe selected planar face of the partition.
 5. An apparatus for filteringa natural gas stream, the apparatus comprising: a closed vessel having alength and an initially open interior; a partition disposed within thevessel interior, the partition having a planar inner and planar outerside, respectively, dividing the vessel interior into a first stage anda second stage; at least one opening in the partition; an inlet port influid communication with the first stage; an outlet port in fluidcommunication with the second stage; at least one tubular filterelement, the tubular filter element being disposed within the vessel tosealingly extend from within the first stage, the filter element havinga locking end, a tubular length, and a handle end; a mounting structurelocated on a selected planar side of the partition; a rotationalmounting means on the locking end of the at least one filter elementwhich cooperates with the mounting structure of the vessel forrotationally locking the filter element with respect to the partitionupon rotational movement of the filter element from the handle end;wherein each of the filter elements has a generally cylindrical lockingend and wherein the mounting means on the locking end of the filterelements is a slot provided in the cylindrical locking end; wherein themounting means on the locking end of the filter elements is a J-slot;wherein the mounting structure located on a selected side of thepartition is a pair of spaced apart post elements which are aligned withrespect to a partition opening and wherein the J-slot receives andengages the post elements as the filter element is rotated from thehandle end; and wherein the post elements are supported between opposingside flanges, the side flanges being arranged generally perpendicular tothe selected planar face of the partition, whereby the spaced apart postelements extend in a plane generally parallel to the plane of theselected planar face of the partition.
 6. A tubular filter element forfiltering a natural gas stream passing through a filter vessel, thefilter element comprising: a body having a locking end, a tubular lengthand a handle end; the tubular length of the filter body comprising afilter wall having a plurality of overlapped layers of non-woven fabricstrips, the filter body also having a hollow core; a rotational mountingmeans on the locking end of the filter element which cooperates with amating mounting structure provided within the filter vessel forrotationally locking the filter element with respect to the mountingstructure upon rotational movement of the filter element from the handleend; wherein the locking end of the filter element is a generallycylindrical locking end and wherein the mounting means on the lockingend of the filter element is a slot provided in the cylindrical lockingend; and wherein the generally cylindrical locking end of the filterelement joins the tubular length of the filter element at a neck regionof each filter element, the neck region forming a region of increasedexternal diameter along the tubular length of the filter element, andwherein a seal means is located at the neck region for sealing againstthe mounting structure when the filter element is locked in position. 7.The filter element of claim 6, wherein the seal means is achevron-shaped seal.
 8. The filter element of claim 6, wherein the sealmeans is an O-ring seal.
 9. A method of filtering solids from a naturalgas stream, the method comprising the steps of: providing a filtervessel having a first stage and a second stage, the first stage beingseparated from the second stage by a partition having at least oneopening; installing at least one replaceable filter element within thefilter vessel, the filter element being sealed within the opening in thepartition, the filter element having a locking end, a tubular length,and a handle end; providing a mounting structure located on a selectedplanar side of the partition; providing a rotational mounting means onthe locking end of at least selected filter elements which cooperateswith the mounting structure of the vessel for rotationally locking thefilter element with respect to the mounting structure upon rotationalmovement of the filter element from the handle end; filtering solidsfrom the gas stream in the first stage; and passing the gas stream fromthe filter element to the second stage; wherein the filter elements areprovided with generally cylindrical locking ends and wherein themounting means on the locking end of the filter elements is a slotprovided in the cylindrical locking end; and wherein the generallycylindrical locking end of the filter elements join the tubular lengthof the filter elements at a neck region of each filter element, the neckregion forming a region of increased external diameter along the tubularlength of the filter element, and wherein a seal means is located at theneck region for sealing against the partition when the filter element islocked in position.
 10. The method of claim 9, wherein the seal means isa chevron-shaped seal.
 11. The method of claim 9, wherein the seal meansis an O-ring seal.
 12. An apparatus for filtering a natural gas stream,the apparatus comprising: a closed vessel having a length and aninitially open interior; a partition disposed within the vesselinterior, the partition having a planar inner and planar outer side,respectively, dividing the vessel interior into a first stage and asecond stage; an inlet port in fluid communication with the first stage;an outlet port in fluid communication with the second stage; at leastone opening in the partition sized to receive a locking end of a tubularfilter element for supporting the filter element within the vessel; amounting structure located on a selected planar side of the partition,the mounting structure comprising at least one post supported by sideflanges so that the post lies in a plane which extends at least partlyacross the opening in the partition; and wherein the post is supportedbetween opposing side flanges, the side flanges being arranged generallyperpendicular to the selected planar face of the partition, whereby thepost extends in a plane generally parallel to the plane of the selectedplanar face of the partition.
 13. An apparatus for filtering a naturalgas stream, the apparatus comprising: a closed vessel having a lengthand an initially open interior; a partition disposed within the vesselinterior, the partition having a planar inner and planar outer side,respectively, dividing the vessel interior into a first stage and asecond stage; an inlet port in fluid communication with the first stage;an outlet port in fluid communication with the second stage; at leastone opening in the partition sized to receive a locking end of a tubularfilter element for supporting the filter element within the vessel; amounting structure located on a selected planar side of the partition,the mounting structure comprising at least one post supported by sideflanges so that the post lies in a plane which extends at least partlyacross the opening in the partition; wherein the mounting structurelocated on a selected side of the partition is a pair of spaced apartpost elements which are aligned with respect to a partition opening; andwherein the post elements are supported between opposing side flanges,the side flanges being arranged generally perpendicular to the selectedplanar face of the partition, whereby the spaced apart post elementsextend in a plane generally parallel to the plane of the selected planarface of the partition.
 14. An apparatus for filtering a natural gasstream, the apparatus comprising: a closed vessel having a length and aninitially open interior; a partition disposed within the vesselinterior, the partition having a planar inner and planar outer side,respectively, dividing the vessel interior into a first stage and asecond stage; an inlet port in fluid communication with the first stage;an outlet port in fluid communication with the second stage; at leastone opening in the partition sized to receive a locking end of a tubularfilter element for supporting the filter element within the vessel; amounting structure located on a selected planar side of the partition,the mounting structure comprising at least one post supported by sideflanges so that the post lies in a plane which extends at least partlyacross the opening in the partition; and wherein a filter element isretrofitted to be installed within the apparatus, the filter elementcarrying mounting means for engaging the partition opening of theapparatus.
 15. The apparatus of claim 14, wherein the mounting means isan element attachment rod which is carried by the conventional filterelement.
 16. The apparatus of claim 15, wherein the element attachmentrod has an engagement end which engages the at least one post supportedby the side flanges of the mounting structure of the apparatus.